Crepidiastrum, in the circumscription used here, includes Paraixeris, following the conclusions by Pak and Kawano (Mem. Fac. Sci. Kyoto Univ., Ser. Biol. 15: 29-61. 1992) of their carpological and cytological investigations, which have been corroborated through recent molecular phylogenetic analyses by J. W. Zhang et al. (in prep.). The analyses by J. W. Zhang et al., moreover, revealed that the Youngia segregate Crepidifolium is also nested within the Crepidiastrum clade, thus confirming an earlier assumption by Sennikov (Bot. Zhurn. 82(5): 113-116. 1997), which Sennikov later revised in favor of establishing the separate genus Crepidifolium (Sennikov & I. D. Illarionova, Komarovia 5: 96. 2008). This genus is therefore also treated here as a congener of Crepidiastrum, extending its geographical range to C Asia. Its basic chromosome number is x = 5.